Atezolizumab-induced myositis and myocarditis in a patient with metastatic urothelial carcinoma

Immune-Related Adverse Events Associated with Atezolizumab: Insights from Real-World Pharmacovigilance Data

The advancement of immuno-oncology has brought about a significant shift in cancer treatment methods, with antibody-based immune checkpoint inhibitors like atezolizumab leading the way in this regard. However, the use of this checkpoint blockade can result in immune-related adverse events due to increased T-cell activity. The full spectrum of these events is not yet completely understood. In this study, the United States FDA Adverse Event Reporting System (FAERS) was utilized to investigate immune-related adverse events linked with the use of atezolizumab. The study identified forty-nine immune-related adverse events that affected multiple organ systems, including cardiovascular, respiratory, hematologic, hepatic, renal, gastrointestinal, neurologic, musculoskeletal, dermatologic, endocrine, and systemic disorders. The strongest signals for relative risk occurred for immune-mediated encephalitis (RR = 93.443), autoimmune myocarditis (RR = 56.641), immune-mediated hepatitis (RR = 49.062), immune-mediated nephritis (RR = 40.947), and autoimmune arthritis (RR = 39.382). Despite the morbidity associated with these adverse events, emerging evidence suggests potential associations with improved survival outcomes. Overall, this report sheds light on the widespread immune-related adverse events that cause significant morbidity and mortality in patients with cancer being treated with atezolizumab and brings attention to them for the clinicians treating these patients.

Atezolizumab-induced myositis in a patient with small-cell lung cancer

OBJECTIVE

Myositis, an inflammatory disease affecting muscles, is a rare and potentially fatal immune-related adverse event associated with immune checkpoint inhibitors. There are limited data on its clinical features and management.

CASE PRESENTATION

Atezolizumab, in combination with etoposide and carboplatin, was initiated in the patient diagnosed with metastatic small-cell lung cancer. After four cycles, maintenance atezolizumab was initiated. At the third visit of the maintenance therapy, the patient reported weakness, edema, and tightness in the muscles that had progressed over the course of a week. Mild solid-food dysphagia was also observed. Neutrophilic leukocytosis with elevated creatine phosphokinase (9234 U/L), erythrocyte sedimentation rate (111 mm/h), and transaminase levels were observed. A diagnosis of myositis was considered based on clinical findings. Atezolizumab was omitted and an oral 0.5 mg/kg/day dose of methylprednisolone was administered. The myositis resolved within 10 days. During the treatment of myositis, the patient underwent prophylactic cranial irradiation. The steroid dose was tapered off within 35 days and then atezolizumab was restarted.

CONCLUSION

The literature contains only a few case reports about atezolizumab-induced myositis, highlighting the challenges in defining its clinical features and management. Prompt diagnosis and treatment are crucial to prevent severe complications, such as myocarditis or respiratory muscle paralysis.

A case report and literature review on respiratory failure with immune checkpoint inhibitors: a life-threatening adverse event

Neuromuscular associated respiratory failure is a rare toxicity of immunotherapy for malignant tumors. In most cases, it may overlap with the symptoms of the primary disease or myocarditis, myositis and myasthenia gravis, resulting in difficult etiological diagnosis. Early detection and optimal treatment are still topics that need attention. Here, a case of 51-year-old male lung cancer patient with sintilimab-associated myasthenia gravis, myositis, and myocarditis overlap syndrome involving the diaphragm who developed severe type II respiratory failure was reported. After high-dose methylprednisolone, immunoglobulin and pyridostigmine intravenous injection with non-invasive positive pressure ventilation, the patient's symptoms improved significantly and was discharged. One year later, the patient received immunotherapy again due to tumor progression. After 53 days, he developed dyspnea again. Chest X-ray demonstrated marked elevation of the diaphragm, and the electromyogram demonstrated dysfunction of diaphragm. With rapid diagnosis and timely treatment, the patient was finally discharged safely. A comprehensive search of PubMed, EMBASE was performed to identify all previously reported cases of immune checkpoint inhibitors-associated respiratory failure. The potential mechanisms of respiratory failure caused by ICI-associated diaphragmatic dysfunction may be related to T cell-mediated immune disturbances and we proposed possible diagnostic processes. For patients with unexplained respiratory failure who are receiving immunotherapy, standardized diagnostic strategies should be implemented immediately on admission before deciding whether to conduct a more invasive diagnostic procedure or empirical treatment.

[A case of atezolizumab- and bevacizumab-induced myositis showing high intensity in the pterygoid muscles, soft palate, and tongue on STIR-MRI]

A 61-year-old woman was treated with atezolizumab plus bevacizumab for hepatocellular carcinoma with peritoneal dissemination. Blood tests revealed elevated creatine kinase (CK) that peaked at 2,657 U/l. After two cycles of atezolizumab plus bevacizumab combination therapy, she complained of progressive dysarthria and dysphagia. Needle electromyography showed myopathic changes. Initial MRI showed high signal intensity in the orbicularis oris muscle, soft palate, tongue, pterygoid muscles, and paravertebral muscles on STIR images. Myositis-specific autoantibodies were not detected. Based on these findings, the patient was diagnosed with immune checkpoint inhibitor-associated myositis. The clinical symptoms improved after administration of oral prednisone, and follow-up MRI showed reduced extent of areas of high signal intensity and almost complete resolution of signal abnormality in the paravertebral muscles. The CK level normalized after 1 months of oral steroid administration. MRI of the head and neck, including the tongue and soft palate, may be useful in diagnosis and for evaluating therapeutic efficiency in cases of bulbar symptoms that occur following the introduction of immune checkpoint inhibitors.

Incidence and Distinct Features of Immune Checkpoint Inhibitor-Related Myositis From Idiopathic Inflammatory Myositis: A Single-Center Experience With Systematic Literature Review and Meta-Analysis

Immune checkpoint inhibitor (ICI)-related myositis is a rare, potentially fatal condition that warrants further studies. Its incidence, clinical features, and prognosis remain poorly understood. To address these gaps, we conducted a systematic review and meta-analysis to evaluate the risk of myositis associated with ICI for solid tumors by analyzing phase III randomized controlled trials of anti-programmed death-1/ligand-1 (PD-1/PD-L1) and anti-cytotoxic T-lymphocyte antigen-4 (CTLA-4). To complement this analysis with clinical data, we evaluated published ICI case reports along with cases from our institutional registry. This registry comprised 422 patients treated with ICIs alone or in combination from September 2014 to June 2021. The analysis revealed an incidence of ICI-related myositis in 6,838 patients in 18 randomized controlled trials of 0.38% (odds ratio 1.96; 95% confidence interval 1.02–3.75) for patients receiving ICIs compared with controls. Detailed analysis of 88 cases from the literature search and our registry showed that myositis induced by PD-1 inhibitors was more frequent than that induced by anti-CTLA-4 agents, revealing a clinically diverse trend including myasthenia gravis and myocarditis. Importantly, having ptosis at the time of onset was significantly associated with the development of concomitant myocarditis (odds ratio 3.81; 95% CI 1.48–9.83), which is associated with poor prognosis. Regarding treatment, most patients received glucocorticoids, and some received immunosuppressants. Our study revealed the incidence of ICI-mediated myositis and the clinical features of myocarditis, highlighting the need for recognition and early intervention.

Clinical Characteristics and Outcomes in Immune Checkpoint Inhibitor Therapy-Associated Myocarditis

Immune checkpoint inhibitor (ICI) therapy has played an important role in the treatment of several groups of cancers. Although a life prolonging treatment, many side effects have been shown with ICI therapy. This study looked at individual level clinical characteristics and outcomes with ICI therapy in patients who developed ICI-related myocarditis. A comprehensive review of the National Library of Medicine PubMed database was performed. Inclusion criteria were all studies that were composed of case reports and case series of individual patients undergoing ICI therapy that developed myocarditis. To appreciate individual patient level data, observational studies, clinical trials, systematic reviews, and meta-analyses were excluded. Our search yielded 333 results with 71 cases reviewed of ICI therapy-related myocarditis. The findings included an average age of 68 years, higher incidence in men, and pretreatment cardiac history of hypertension. Melanoma was the most prevalent malignancy with nivolumab being the most used ICI therapy. Heart failure was the most prevalent adverse event that was co-prevalent with myocarditis. Corticosteroid therapy alone was the most utilized therapy to treat ICI-related myocarditis. Mortality was seen in nearly half of the patient population. Our study reviewed the preexisting literature of prior reported myocarditis secondary to ICI therapy. Periodic surveillance should be performed by the cardio-oncologist and internist. Due to the expanding role of ICI therapy in treating a variety of cancer patients, appreciation of its impact on the development of myocarditis is needed.

Immune Checkpoint Inhibitors Mediated Lymphocytic and Giant Cell Myocarditis: Uncovering Etiological Mechanisms

The advent of immune checkpoint inhibitors (ICIs) has revolutionized the field of oncology, but these are associated with immune related adverse events. One such adverse event, is myocarditis, which has limited the continued immunosuppressive treatment options in patients afflicted by the disease. Pre-clinical and clinical data have found that specific ICI targets and precipitate distinct myocardial infiltrates, consistent with lymphocytic or giant cell myocarditis. Specifically, it has been reported that CTLA-4 inhibition preferentially results in giant cell myocarditis with a predominately CD4+ T cell infiltrate and PD-1 inhibition leads to lymphocytic myocarditis, with a predominately CD8+ T cell infiltrate. Our manuscript discusses the latest literature surrounding ICI pathways and targets, while detailing proposed mechanisms behind ICI mediated myocarditis.

Immune Checkpoint Inhibitor-Induced Myocarditis with Myositis/Myasthenia Gravis Overlap Syndrome: A Systematic Review of Cases

BACKGROUND

The development of immune checkpoint inhibitors (ICIs) represents a paradigm shift in the treatment of cancers. Despite showing remarkable efficacy, these agents can be associated with life-threatening immune-related adverse events. In recent years, several cases of myocarditis with myositis and/or myasthenia gravis overlap syndrome (IM3OS) have been reported. However, given the rarity, the clinical features and outcomes of these cases remain poorly understood. We, therefore, attempted to systematically review and summarize all cases of IM3OS reported in the literature.

MATERIALS AND METHODS

Studies reporting IM3OS were identified in Embase and MEDLINE. Only case reports and case series published in journals or presented at conferences were included. We conducted a systematic review according to the PRISMA Harms guidelines.

RESULTS

A total of 60 cases were eligible. The patients' median age was 71 years, and the majority (67%) were males; melanoma was the most common indication for ICIs (38%). The most-reported symptoms were fatigue (80%) and muscle weakness (78%). The median number of doses to the development of IM3OS was one. The average creatine kinase level was 9,645 IU/L. Cardiac arrhythmias occurred in 67% of patients, and 18% had depressed ejection fraction. Initial treatment consisted of immunosuppression with high-dose steroids and supportive therapies. Sixty percent of the patients died in hospital because of acute complications.

CONCLUSION

IM3OS can be associated with significant mortality and morbidity. Prospective studies are needed to understand the optimal approach to diagnose and manage these patients and to develop biomarkers to predict the occurrence and severity of this rare but serious condition.

IMPLICATIONS FOR PRACTICE

Clinicians should suspect coexisting myositis and/or myasthenia gravis in all patients with immune checkpoint inhibitor-induced myocarditis, given their propensity to occur together. Early recognition and prompt treatment with the help of a multidisciplinary team might help improve the outcomes of this life-threatening condition.